Greater than Herpes simplex virus type 2 (HSV-2) now infects the genital tracts of approximately one in five Americans. Strategies to prevent new HSV-2 infections are complicated by its ability to initiate a latent infection in the sensory ganglia, periodically reactivate, and cause recurrent lesions or asymptomatic virus shedding in genital tissues thus increasing its chances of infecting new hosts. Effective vaccines are needed to prevent the establishment of latency within the sensory ganglia. Unfortunately, little is known about the immune mechanisms which protect the sensory ganglia. In animal models, previous genital inoculation with HSV-2 elicits immunity which protects the sensory ganglia from reinfection, thus serving as a paradigm for an effective HSV-2 vaccine. The long term aims of this proposal are to use a murine model of genital HSV-2 inoculation to understand the types of immune mechanisms responsible for protection, how these mechanisms work at the molecular level, and how to elicit these responses to provide long term protection. The results of these studies will provide important information for the rational design of vaccines to protect against HSV-2. In the first aim, a recombinant HSV-2 strain expressing green fluorescent protein (HSV-2 gfp) will be used as a marker to determine if HSV-specific T lymphocytes prevent HSV-2 from reaching the sensory ganglia, thus preventing the establishment of latency. Quantification of HSV-2 gfp infected ganglionic neurons by UV microscopy and HSV-2 gfp genomes in the ganglia by quantitative PCR will be used to demonstrate the role of specific T cell subsets in preventing acute and latent HSV-2 infection of the ganglia. In the second aim, an antibody deficient strain of mice (muMT) will be used to determine the role of HSV-specific antibody in protection of the sensory ganglia. Purified IgG and IgA fractions of HSV-specific sera will be administered to HSV-immune muMT mice to determine the efficacy of specific antibody isotypes in completing the protection of HSV-immune muMT mice against the establishment of latent HSV-2 infection. In the third aim, the ability of immune responses elicited by inoculation of distal mucosal or systemic sites to protect the sensory ganglia will be tested. The ability of inoculation at these sites to elicit long term memory immune responses within the vaginal mucosa and associated genital lymphoid tissue which can be rapidly recalled for protection of the vaginal mucosa and sensory ganglia will be assessed.